1. Field of the Invention
This application relates to electronic article surveillance (EAS) tags, and more particularly to a reusable EAS tag that is proximity detached by electromagnetic energy.
2. Description of the Related Art
Electronic article surveillance systems are well known in the art and are used in many applications including inventory control and to prevent theft and unauthorized removal of articles from a controlled area. Typically, in such systems a system transmitter and a system receiver are used to establish a surveillance zone, which must be traversed by any articles being removed from the controlled area.
An EAS tag is affixed to each article and includes a marker or sensor adapted to interact with a signal being transmitted by the system transmitter into the surveillance zone. This interaction causes a further signal to be established in the surveillance zone which further signal is received by the system receiver. Accordingly, upon movement of a tagged article through the surveillance zone, a signal will be received by the system receiver identifying the unauthorized presence of the tagged article in the zone.
Certain types of EAS tags have been designed to be reusable and, thus, include releasable attachment devices for affixing the tags to the articles. Such attachment devices are further designed to be releasable by authorized personnel only so that unauthorized removal of a tag from its article is avoided. To this end, many attachment devices are made releasable only through the use of an associated special tool or detaching mechanism.
An EAS tag employing an attachment device and an associated detacher is described in U.S. Pat. No. 3,942,829, entitled Reusable Security Tag, issued to Humble, et al. on Mar. 9, 1976. The EAS tag of the '829 patent includes a tag body and an attachment device in the form of a tack assembly. The tack assembly includes an enlarged head and a tack body having a pointed end, which serves to pierce through an article and to be receivable in and clamped to the tag body. This secures the article and tag together.
In the tag of the '829 patent, the tack is clamped to the tag body using a spring clamp formed as a clutch lock with spreadable jaws. Once the article is pierced, the pointed tack end is received in the tag body and is secured between the jaws of the clutch lock. This locks the tack and the tag body forming the EAS tag to the article so that the tag and article cannot be readily separated from each other.
In order for authorized personnel to be able to release the tack from the clutch lock and, therefore, the tag from the article, the '829 patent utilizes a detacher mechanism which is adapted to grip the tag body and apply a bending force thereto. This force is sufficient to deform the clutch lock so that the jaws of the clutch lock are spread apart, thereby releasing the tack. The tack can then be removed from the tag body so that the article and tag become separated from one another.
To permit the bending of the tag body sufficiently to deform the clutch lock, the tag body of the '829 patent must be made of a flexible material. Typically, flexible plastic materials such as, for example, polypropylene, have been used. Such materials, however, are susceptible to being cut and damaged. This tends to be a disadvantage, since it increases the likelihood that the locking feature of the tag can be separated from the EAS sensor part of the tag or can be exposed and defeated.
Another type of EAS security device is known in which a variation of the spring clamp of the '829 patent has been incorporated into a so-called keeper for a compact disc. This type of device is disclosed in U.S. Pat. No. 5,031,756, entitled Keeper For Compact Disc Package Or The Like, issued to Buzzard, et al. on Jul. 16, 1991.
The keeper of the '756 patent comprises a rigid plastic frame. One side of the frame is provided with an enlarged section which houses a tack-like button assembly and a spring clamp as in the '829 patent. In this case, the spring clamp is used to lock the button assembly in a first position. In this position, the pointed end of the button assembly protrudes into the frame to pierce and hold to the frame a cardboard container containing a compact disc. As a result, unauthorized removal of the compact disc with the frame causes an EAS sensor also incorporated into the frame, to generate a detectable signal for alarming an EAS system.
In the keeper of the '756 patent, the enlarged section of the frame is provided with opposing linear slots, which lead to the region between the jaws of the spring clamp. By inserting ramped linear fingers into these slots, the fingers are guided into this region, causing the jaws to flex outward. This releases the button enabling it to be withdrawn from the cardboard container. The container and its housed compact disc can then be separated from the frame.
While the keeper of the '756 patent utilizes a spring clamp of the '829 patent type in a rigid frame, it also has certain drawbacks. One drawback is that the linear slots leading to the spring clamp permit in-line viewing and access to the clamp. This increases the susceptibility of the clamp to defeat, since linear objects can be inserted into the slots in an attempt to open the jaws. Another drawback is that the fingers of the detacher are required to be of high precision, since they must be received in the region between the spring clamp jaws. This increases the cost and complexity of the detacher.
U.S. Pat. No. 5,426,419, entitled Security Tag Having Arcuate Channel And Detacher Apparatus For Same, issued to Nguyen, et al. on Jun. 20, 1995, discloses an EAS tag that has a hard tag body, which is adapted to be releasable from an article in an easy and simple manner by insertion of an arcuate probe of an associated detacher device into an arcuate channel of the tag to release a spring clamp mechanism. The spring clamp mechanism is a releasable locking mechanism that prevents removal of the tack assembly that is adapted for insertion through an article, which is captured when inserted into an opening in a portion of the tag body. The EAS tag of the '419 patent is more difficult to defeat than the above tags and is in worldwide use.
The EAS tag of the '419 patent can be defeated by insertion of a segment of relatively rigid metal bent in an arcuate manner to simulate the arcuate probe of the associated detacher device. U.S. Pat. No. 6,373,390, entitled Electronic Article Surveillance Tag Having Arcuate Channel, issued to Hogan, et al. on Apr. 16, 2002, discloses a device usable in the EAS tag of the '419 patent to reduce the potential for defeats by insertion of simulated arcuate probes. As each improvement in defeat resistance is implemented, new techniques for unauthorized tag removal are developed. An improved EAS tag detachment mechanism is needed to reduce the incidence of unauthorized EAS tag detachments.
An alternate to a reusable EAS tag is a disposable EAS tag or EAS label. Instead of detachment from an article that is authorized for removal, EAS labels are typically deactivated so they do not interact with the EAS surveillance zone and are not detected by the associated EAS receiver when the article is removed. Deactivation is normally accomplished by exposing the label to an electromagnetic field or pulse of preselected waveform, frequency, amplitude, and/or duration. Deactivation normally occurs near the cash register in a retail environment, and may be linked to a barcode scanner or to radio frequency identification (RFID) equipment. In some cases, the deactivator equipment may be triggered as the article is scanned for checkout.
U.S. Pat. No. 5,867,101, entitled Multi-Phase Mode Multiple Coil Distance Deactivator for Magnetomechanical Marker, issued to Copeland, et al. on Feb. 2, 1999, and U.S. Pat. No. 6,060,988, entitled EAS Marker Deactivation Device Having Core-Wound Energized Coils, issued to Copeland, et al. on May 9, 2000, disclose deactivators suitable for deactivating magnetomechanical or acoustomagentic EAS labels and are available from Sensormatic Electronics Corporation, Boca Raton, Fla. Deactivators for radio frequency (RF), and other technology EAS labels are also commercially available. In some instances, retail merchants may use reusable EAS tags and disposable EAS labels in one store, which requires separate detaching and deactivation mechanisms for different purchases. If a deactivator could be used to detach EAS tags, the burden of the retailer to have multiple mechanisms would be eliminated, and the mechanical techniques for unauthorized detaching of EAS tags could also be reduced.
In addition, detaching of EAS tags requires the presentation of the tag to the detaching device and/or the application of mechanical force by the operator. Detaching by simply placing the EAS tag in proximity to a detaching mechanism would speed up the detaching process, thereby reducing the time required for each transaction, decreasing costs, and increasing customer satisfaction.